Field of the Invention
The present invention relates to an electric power tool in which a tool tip is attached to an output shaft.
Description of the Related Art
An electric power tool that is referred to as a dust-proof board trimmer or a cutout tool used in a processing operation such as cutting of a gypsum board is well known (for example, refer to “Dust-proof Board Trimmer Model 3706 User Manual (Cutout Tool 3706 Instruction Manual)” published by Makita Corporation in February 2006). This type of electric power tool generally includes a driving motor that generates a rotary driving force, and an output spindle (output shaft) that is rotated according to the rotating force of the driving motor. An attachment mechanism to which a processing bit (tool tip) is attached is arranged at a tip of the output spindle. A bit that is selected in accordance with a processing such as the above-described cutout processing is attached to the attachment mechanism. The attachment mechanism is configured in such a manner that various types of bits can be attached for replacement. In general, this type of attachment mechanism is configured to be fastened with a nut. Such a fastening nut can be loosened or tightened with a spanner.
It is desired that the spanner be used with respect to a nut in another electric power tool.
However, if a user has to always prepare a spanner for the electric power tool, the user will be burdened with the preparation and management of the spanner. Thus, there is a need in the art to reduce the burden of ready-to-use preparation and management of the spanner.
The present invention provides an electric power tool in which a tool tip is attached to an output shaft without having to increase the number of components of the electric power tool to be equipped such that the burden of ready-to-use preparation and management of required tools can be reduced for a user.